Polyvinyl acetal resin sheets containing di-(2-(beta -butoxyethoxy)-ethyl-) formal



Patented Dec. 5, 1939 PATENT OFFlCE roLYvmrL ACETAL imsm SHEETS CON- TAINING m- (2- (p-nu'roxm'rnoxm- ETHYL-) FORMAL noni- B. Smith and Donald B. Swan, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application December 22 1937.-

Serial No.-1s1,225

4 'Claims.

This invention relates to plastic compositions, and more particularly to compositions comprising a polyvinyl acetal resin and a conditioning agent.

One object of this invention is to produce compositions of matter which may be made into permanently transparent, strong and flexible sheets or films of desired thinness which are substantially waterproof, are unaffected by ordinary photographic fluids and possess the desired properties of a support for sensitive photographic coatings. Another object of our invention is to produce compositions of matter which can be made into sheets suitable for use in laminated, shatter-proof glass. Still another object is to produce compositions which can be rolled, extruded, molded or otherwise worked into relatively thick sheets and massive plastics. A further object is to produce compositions suitable for use in lacquers, artificial silk filaments, wrapping tissues and the like. Other objects will hereinafter appear.

We have discovered that di-(2-(B-butoxy- -ethoxy)-ethyl-) formal is a very useful conditioning agent for polyvinyl acetal resins. Not only does it serve as a plasticizer in the accepted sense of the term, increasing the flexibility and toughness of polyvinyl acetal resin films, sheets, or other objects or masses containing it, but when used in amounts of about or more parts per 100 parts of certain of the polyvinyl acetal resins, namely the polyvinyl acetal resins in which a predominating proportion of the acetal groups are acetaldehyde acetal groups or butyraldehyde acetal groups, it has an unusual and remarkable effect which we may call elasticizing.

That is to say, a sheet of polyvinyl 'acetaldehyde or butyraldehyde acetal resin containing about,

and may be prepared as follows:

300 g. (2.7 gram-moles) of calcium chloride is dissolved as completely as possible in 2000 g.

formal has (12.4 gram-moles) of diethylene glycol monobutyl ether by heating to l-190 C. with stirring; The mixture is cooled to about C., and 240 g. (8 gram-moles of CHzO) oftrioxymethylene is added and well mixed in. The mixture is heatedin an oil bath, with frequent shaking, to about -145 C., at which temperature refluxing begins. Refluxing is continued for about three hours. The mixture is then cooled to room temperature, and the top layer is decanted and distilled. The material coming over up to'1'.75 C. at normal pressure is discarded. The residue is cooled to 100 C. and distilled under reduced pressure. The fraction coming over up to 198 C. at 7 mm. pressure is discarded. The di-(2- B-butoxyethoxy) -ethyl-) formal distills over at 199-209 C. at '7 mm. pressure. It is insoluble in water.

For the manufacture of cast films or sheets, the polyvinyl acetal resin and di-(Z-(B-butoxyethoxy)-ethyl-) formal may be dissolved in asuitable solvent or solvent mixture, such, for instance, as acetone, methanol, acetone-methanol mixtures, ethylene chloride-methanol mixtures, etc., about 300 to 500 or more parts of the solvent or solvent mixture being used per 100 parts of the resin. From about 2 to 100 parts or more of di-(2-(B-butoxyethoXy)-ethyl-) formal per 100 parts of resin may be employed, depending upon the nature of the resin and the purpose for which the sheets are to be used. Suitable proportions of di- (2- (B-butoxyethoxy) -ethyl-) formal for any resin and any purpose may be 'readily determined by experiment. For the manufacture of sheets suitable for photographic film base, 2 to 25 parts of di-(2-(B-butoxyethoxy) -ethy1-) formal per 100 parts of resin are suitable. The resin solution is cast as a sheet, the solvent evaporated, and the sheet stripped from the casting surface.

Sheets for use in laminated glass may be formed by casting, or may be made without the use of volatile solvent by extrusion, for example in the manner set forth in application Serial No. 147,934 of John S. Kimble and Ernest C. Blackard, flled June 12, 1937. For instance, 40 or more parts of di-lZ-(B-butoxyethoxy)-ethyl-) formal and 100 parts of a polyvinyl acetaldehyde or butyraldehyde acetal resin may be mixed in a suitable, jacketed mixer at a low temperature, for example 10 C., and the mixture may then be worked on hot rolls, in the manner described in U. S. Patent 2,048,686 of F. R. Conklin, until complete homogenization has taken place. The mass thus produced may then be extruded through an annular die, and thetube so formed slit to form a sheet. m The polyvinyl acetal resins can be prepared by reacting polyvinyl alcohol with an aldehyde'irn prepared by simultaneously de-esterifying a polyvinyl aliphatic ester and reacting the de-esterification product with'an aldehyde in the presence of a de-esterifying catalyst and acetal condensation catalyst. Mineral acids are catalysts for both de-esterification and acetal formation. Among the polyvinyl acetal resins with which di- (2-(B-butoxyethoxy)-ethyl-) formal is useful may be mentioned, as illustrative examples; the polyvinyl formaldehyde acetal resins, the polyvinyl acetaldehyde acetal resins, the polyvinyl formaldehyde acetaldeyde mixed acetal resins, the polyvinyl butyraldehyde acetal resins, and the polyvinyl butyraldehyde acetaldehyde mixed acetal resins.

Examples of the preparation of polyvinyl formaldehyde acetal resins may be found in U. S. Patent 1,955,068, Examples 1, 4 and 5; in U. S. Patent 2,036,092, Examples 1, 2, 3, 7 and 8; in British Patent 454,691, Examples 1, 2, 3, 4, 5, 6 and 7; in British Patent 404,279, Example 3; and, in British Patent 436,072, Examples 1, 2, 3, 4, 5, 6 and 7.

Examples of the preparation of polyvinyl acetaldehyde acetal resins maybe found in U. S. Patent 2,044,730, Example 1; U. S. Patent 1,955,068, Example 2; U. S. Patent 2,036,092, Examples 4, 5 and 6; British Patent 466,598, Ex.- amples 1, 2, 3, 4 and 7; British Patent 404,279, Examples 1, 2, 4, 5, 6, 7 and 8; U. S. Patent 1,990,399; and French'Patent 808,578, Examples 1,2and3.

Additional examples of the preparation of polyvinyl acetaldehyde acetal resinsare as follows: 100 lbs. of polyvinyl acetate, the viscosity of whose molar, solution in benzene was 45 centipoises, was dissolved in 300 lbs. of 95% ethyl al cohol. To this solution were added lbs. of paraldehyde and 25'lbs. of HCl. The reaction mixture was allowed to stand for 4 days at 40 C., after which it was diluted with ethyl alcohol, and the resin precipitated by pouring into cold water, washed and dried. Analysis showed the resin to have an acetate group content equivalent to 2.1% by weight of polyvinyl acetate and a hydroxyl group content equivalent to 12.9% by weight of polyvinyl alcohol.

25 lbs. of polyvinyl acetate, the viscosity of whose molar solution in benzene was centipoises, was dissolved in lbs. of ethyl alpolyvinyl acetate and a hydroxyl group content equivalent alcohol.

Examples of the preparation of polyvinyl formto 13.8% by weight of polyvinyl aldehyde acetaldehyde mixed acetal resins may be found in British Patent.430,136, Examples 1, 2,

,3, 4, 5, and 6; British Patent 445,565, Example 2;

British Patent 465,873, Examples 1,2,3, 4, 5, and

,6; French Patent 808,586, Examples 1, 2, 3, 4,5}

6, 12, 13, 14, 15, 16, 17, 1a and 19.

Additional examples of the preparation of polyvinyl formaldehyde acetaldehyde mixed acetal resins are-given in the application of Ralph H. Talbot, Serial No. 85,960, filed June 18, 1936, as follows:

' Example 1 parts (1.16 mol. calculated as monomeric vinyl acetate). of a polyvinyl acetate (45 centipoises), 100 parts of ethyl alcohol, parts of ethyl acetate, 34 parts (.77 mol. as monomeric acetaldehyde) of paracetaldehyde and 5.8 parts- (.196 mol. as monomeric formaldehyde) of paraformaldehyde were placed in an enamelled vessel and brought into solution by stirring. when solution was complete, 10' parts of sulfuric acid -(sp. g. 1.84) in 10 parts of water were added, and

the mixture stirred. The mixture was maintained weightof polyvinyl formaldehyde acetal and anacetaldehyde acetal group content equivalent to about 73.9 per cent by weight of polyvinyl acetaldehyde acetal, The polyvinyl acetal p'ortion of the resin was therefore made up of about 19.7

per cent by' moles of polyvinyl formaldehyde acetal and about 80.3 per cent by moles of polyvinyl acetaldehyde acetal. The resin was soluble in acetone to anextent which permitted coating a film or sheet, from the resin. l Erample 2 cohol, 90 parts of ethyl acetate, 17 parts (.385

50 parts (.58 mol. as monomer) of polyvinyl acetate (45 centipoises), '50 parts of ethyl al-- mol. as monomer) of paracetaldehyde, 2.9 parts (.098 mol. as monomer) of paraiormaldehyde, 5 parts of sulfuric acid and 5 parts of water were treated as in Example 1 for 161 hours. The well washed and dried resin gave upon analysis a hydroxyl group content equivalent to about 9.6% w by weight of polyvinyl alcohol, an acetate group I "Emmple3 I 1300 parts (15.1 mol. as monomer) of a polyvinyl acetate (45 centipoisos), 1700 parts of ethyl acetate, 2250parts of ethylplcohol (95%) and 48 parts (1.57 mol. as monomer) of paraformaldehyde (trioiwmethylene) were 'placedin a vessel equipped with 'a reflux condenser and a means of agitation, and the contents brought to a temperature of about 70 C. by means of steam heat- 76 amazes ing. 182.25 parts of sulfuric acid (sp. g. 1.84) dissolved in 51.5 parts of water were added, and the whole was heated at about 70? C. for about five hours, agitating throughout. At this point, 266.4 parts (6.05 mol. as monomer) of paracetaldehyde were added and heating at about 70 C.

Patent 466,598, Example 'of twenty hours,

with agitation was continued for afurther period The contents of the reaction vessel were neutralized with ammonium hydroxide and diluted with water precipitating the resin as a cake, and repeatedly washed with hot water until the resin was free from solvents, salts and other impurities. The resin, upon analysis, showed a hydroxyl group content equivalent to about 10.1 per cent by weight of polyvinyl alcohol, an acetate group content equivalent to about 3.2 per cent by weight of polyvinyl acetate, the remainder of the weight of the resin being polyvinyl acetal. The polyvinyl acetal portion of the resin was made up of about 80 per cent by moles of polyvinyl acetaldehyde acetal and about 20 per cent by moles of polyvinyl formaldehyde acetal. The resin was not quite soluble'in acetone, but could be'made to dissolve by admixing small amounts of other solvents, such as alcohols, with the acetone. I

-Examples of the preparation of polyvinyl butyraldehyde acetal resins may be found in U. S.

Patent 2,044,730, Examples 2, 5 and 6; British 813,303, Example 1; French Patent 813,514, Examples 1, 2, 3 and 4; and British Patent 459,878, Examples 1, 2, 5, 6, 7-, 8, 9 and 10.

An additional example of the preparation of a polyvinyl butyraldehyde acetal resin is as follows:'

23.6 lbs. of polyvinyl acetate, the viscosity of whose molar solutionin benzene was 45 centipoises, was'dissolved in 56.5 lbs. of 95% ethyl alcohol. To this solution were added 7.9 lbs. of butyraldehyde and 5.9 lbs. of 35% I101. The reaction mixture was allowed to stand for 4 days at The cake was cut into small News French Patent 40 (2., after which it was diluted with ethyl alcohol and acetic acid, and the resin precipitated by pouring into cold water, washed, and dried. An-

- An example of the preparation of a polyvinyl butyraldehyde:acetaldehyde mixed acetal resin is given in French Patent 813,303,-Example 2.

What we claim as our invention and desire to be secured by letters @Patent of the United States is:

1. A transparent, rubbery sheet comprising 100 parts of a polyvinyl acetal resin in which a predominating proportion of the acetal groups are selected from the group consisting of acetaldehyde acetal groups and butyraldehyde acetal groups, v and at least 40* parts, approximately, of di-(2- parts of a polyvinyl butyraldehyde acetal resin and at least 40 parts, approximately, of di-(2-B- butyoxyethoxy) -ethy1-) formal .as an elasticizer therefor.

4 A transparent, rubbery'sheet comprising a polyvinyl acetal resin in which a predominating proportion of the acetal groups are selected from the group consisting of acetaldehyde acetal groups and butyraldehyde acetal groups, and an amount of di-(2-(p-butoxy-ethoxy) -ethyl formal sumcient to impart to the sheet a rubbery character without substantially impairing its transparency.

. HENRY B. SMITH. R. SWAN. 

